Communication system monitor

Abstract

A monitor for a communication system injects a shaped pulse into the communication system at a first point. The shaped pulse has a short time duration to enable the integrity of the communication system to be monitored in a short amount of time. The shaped pulse also has a narrow frequency spectrum to avoid interference with live signals present in the communication system. The monitor includes a source generating a carrier signal having an adjustable frequency, a modulator receiving the carrier signal and modulating the carrier signal to provide the shaped pulse. Alternatively, the monitor includes a signal source directly providing the shaped pulse. A receiver within the monitor detects the shaped pulse at one or more second points in the communication system. The shaped pulse is below live signals within the communication system by a predesignated threshold at a predetermined frequency offset from the frequency of the carrier signal.

What is claimed is:  
     
         1 . A monitor for a communication system, comprising: 
 a source generating a carrier signal adjustable to at least one predesignated frequency;    a modulator receiving the carrier signal and modulating the carrier signal according to a control signal to provide a shaped pulse;    a coupler, injecting the shaped pulse into the communication system at a first point, in the presence of at least one live signal within the communication system; and    a receiver, detecting the shaped pulse at at least one second point in the communication system, wherein the shaped pulse is below the at least one live signal by at least a predesignated threshold at a predesignated offset from each of the at least one predesignated frequency of the carrier signal, and wherein the shaped pulse has a time duration that is less than a settling time of the source and the receiver.    
     
     
         2 . The monitor of  claim 1  wherein the shaped pulse has an envelope that is a truncated SINC shape.  
     
     
         3 . The monitor of  claim 1  wherein the shaped pulse includes a transition period that accommodates the settling time of the source and the receiver, the time duration of the shaped pulse being less than ten percent of the transition period.  
     
     
         4 . The monitor of  claim 2  wherein the shaped pulse includes a transition period that accommodates the settling time of the source and the receiver, the time duration of the shaped pulse being less than ten percent of the transition period.  
     
     
         5 . The monitor of  claim 1  wherein detecting the shaped pulse includes measuring an amplitude of the shaped pulse at the at least one second point with the carrier signal adjusted to multiple ones of the at least one predesignated frequencies.  
     
     
         6 . The monitor of  claim 2  wherein detecting the shaped pulse includes measuring an amplitude of the shaped pulse at the at least one second point with the carrier signal adjusted to multiple ones of the at least one predesignated frequencies.  
     
     
         7 . The monitor of  claim 3  wherein detecting the shaped pulse includes measuring an amplitude of the shaped pulse at the at least one second point with the carrier signal adjusted to multiple ones of the at least one predesignated frequencies.  
     
     
         8 . A monitor for a communication system, comprising: 
 a signal source generating a shaped pulse including a carrier signal adjustable to at least one predesignated frequency;    a coupler, injecting the shaped pulse into the communication system at a first point, in the presence of at least one live signal within the communication system; and    a receiver, detecting the shaped pulse at at least one second point in the communication system, wherein the shaped pulse is below the at least one live signal by at least a predesignated threshold at a predesignated offset from each of the at least one predesignated frequency of the carrier signal, and wherein the shaped pulse has a time duration that is less than a settling time of the signal source and the receiver.    
     
     
         9 . The monitor of  claim 8  wherein the shaped pulse has an envelope that is a truncated SINC shape.  
     
     
         10 . The monitor of  claim 8  wherein the shaped pulse includes a transition period that accommodates the settling time of the source and the receiver, the time duration of the shaped pulse being less than ten percent of the transition period.  
     
     
         11 . The monitor of  claim 9  wherein the shaped pulse includes a transition period that accommodates the settling time of the source and the receiver, the time duration of the shaped pulse being less than ten percent of the transition period.  
     
     
         12 . The monitor of  claim 8  wherein detecting the shaped pulse includes measuring an amplitude of the shaped pulse at the at least one second point with the carrier signal adjusted to multiple ones of the at least one predesignated frequencies.  
     
     
         13 . The monitor of  claim 9  wherein detecting the shaped pulse includes measuring an amplitude of the shaped pulse at the at least one second point with the carrier signal adjusted to multiple ones of the at least one predesignated frequencies.  
     
     
         14 . The monitor of  claim 10  wherein detecting the shaped pulse includes measuring an amplitude of the shaped pulse at the at least one second point with the carrier signal adjusted to multiple ones of the at least one predesignated frequencies.  
     
     
         15 . A monitoring method for a communication system, comprising: 
 generating a carrier signal adjustable to at least one predesignated frequency;    modulating the carrier signal according to a control signal to provide a shaped pulse;    injecting the shaped pulse into the communication system at a first point, in the presence of at least one live signal within the communication system; and    detecting the shaped pulse at at least one second point in the communication system, wherein the shaped pulse is below the at least one live signal by at least a predesignated threshold at a predesignated offset from each of the at least one predesignated frequency of the carrier signal, and wherein the shaped pulse has a time duration that is less than a pre-established settling time.    
     
     
         16 . The monitoring method of  claim 15  wherein the shaped pulse has an envelope that is a truncated SINC shape.  
     
     
         17 . The monitoring method of  claim 15  wherein the shaped pulse includes a transition period that accommodates the pre-established settling time, the time duration of the shaped pulse being less than ten percent of the transition period.  
     
     
         18 . The monitoring method of  claim 16  wherein the shaped pulse includes a transition period that accommodates the pre-established settling time, the time duration of the shaped pulse being less than ten percent of the transition period.  
     
     
         19 . The monitoring method of  claim 15  wherein detecting the shaped pulse includes measuring an amplitude of the shaped pulse at the at least one second point with the carrier signal adjusted to multiple ones of the at least one predesignated frequencies.  
     
     
         20 . The monitoring method of  claim 16  wherein detecting the shaped pulse includes measuring an amplitude of the shaped pulse at the at least one second point with the carrier signal adjusted to multiple ones of the at least one predesignated frequencies.